Vehicle tire deflation signalling system

ABSTRACT

A mechanism for actuating signalling means primarily at the operator&#39;&#39;s station of an automotive vehicle to indicate deflation or under inflation of a pneumatic tire on any of the loadcarrying wheels of the vehicle, mechanical means carried by the wheels being provided for actuating an electrical switch positioned on a relatively fixed portion of the vehicle to activate the signalling means upon the pressure in the adjacent tire falling below a predetermined value.

United States Patent [191 Winther s4 VEHICLE TIRE DEFLATION SIGNALLINGSYSTEM [75] Inventor: Harry C. Winther, Glen Mills, Pa.

[731 Assignees: Harry C. Winther; Walter J.

' Winther; Charles R. Winther; William J. Winther; Shirley N. Winther,

; part interest to each [22] Filed: Feb. 8, 1971 [21] Appl. No.: 113,566

[52] US. Cl ..340/58, ZOO/61.25 [51] Int. Cl ..B60c 23/02 [58] Field ofSearch ..340/58; 200161.22, 61.25

[56] a References Cited UNITED STATES PATENTS 2,958,746- 11/1960Hawkins....- ..200/6l.25

, Hu h 111 3,717,845 51 Feb. 20, 1973 l/l943 Thorson ..340/58X 8/1958Amundsen,Jr.etal ..340/58 Primary Examiner-Alvin l-l. WaringAttorney-Wycliff Walton [5 7 ABSTRACT A mechanism for actuatingsignalling means primarily at the operators station of an automotivevehicle to indicate deflation or under inflation of a pneumatic tire onany of the load-carrying wheels of the vehicle, mechanical means carriedby the wheels being provided for actuating an electrical switchpositioned on a relatively fixed portion of the vehicle to activate thesignalling means upon the pressure in the adjacent tire falling below apredetermined value.

6 Claims, 4 Drawing Figures VEHICLE TIREDEFLATION SIGNALLING SYSTEMBACKGROUND OF THE INVENTION Modern automotive vehicles, especiallytrucks and buses of considerable weight and load carrying capacity areusually equipped with pneumatice road engaging tires which are veryexpensive and readily damaged if forced to support a normal load indeflated or under-inflated condition. The possible causes ofdeflation'and under-inflation are many and it is important not only forthe protection of the tires but also for the safety of the vehicle thatknowledge of deflation and under-inflation be conveyed to the operatoras promptly as possible after its occurence.

There have heretofore been suggested many devices for signalling to theoperator upon failure of any of the tires of automotive vehicles tomaintain proper pressure, usually involving the establishment of anelectrical alarm circuit utilizing the wheel bearings as conductors inthe circuit, which is undesirable.

FIELD OF THE INVENTION In accordance with the present invention there isno utilization of the wheel bearings of a vehicle as conductors of analarm circuit, the electrical components of my apparatus being carriedentirely on the vehicle frame and body, and thus maintained stationarywith respect to the latter and independent of the rotating wheels onwhich the vehicle is supported, a mechanical element carried by eachwheel being provided for actuating an electrical switching element whena condition of under-inflation occurs, but otherwise remaining inactiveand at rest with respect to the wheel during normal operations.

More specifically, the apparatus includes a piston actuated trigger ortripping means projectible into a path intersected by a switch actuatinglever controlling the electrical alarm circuit when the pneumaticpressure in the tire on an associated wheel falls below a predeterminedvalue, air under such reduced pressure then passing to a cylindercontaining a piston which when actuated causes the trigger to beprojected into said path.

DESCRIPTION OF THE PRIOR ART As has been intimated alarm systems withwhich I am familiar designed for the same general purposes and disclosedin the prior art usually depend for their operation upon transmissionthrough the wheel bearings of an electrical alarm circuit, and thusembody contact making means carried by the wheel and rotata- 'ble withit and a brush or other element on the frame part which saidcontactmeans slide as the wheel rotates. While these mechanisms may bepositioned within the wheel brake drum orin some other relativelyprotected location it is difficult to insure their constant readiness tooperate promptly on occurrence of a change in the pressure in theassociated tire.

SUMMARY OF THE INVENTION In the present ap aratus mechanical elementsonly are carried by the w eel and no transmission of electrical orinductive energy from the relatively moving parts of a wheel to thevehicle frame is contemplated.

Moreover, the wheel-borne elements of the apparatus are positioned anddesigned to minimize interference with normal servicing of the vehicletires and to require themselves only minimum attention, while thosecarried by the vehicle frame and body comprise principally relativelysimple electrical elements adapted to be connected with the mainelectrical system of the vehicle and normally need no servicing otherthen resetting after an alarm has been given. The mechanically operatedswitch in the electrical alarm circuit may, however, be an automaticallyresetting one in which case no servicing whatever of the electricalelement of the apparatus will normally be required.

BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawing a preferredembodi- I ment of the invention is illustrated, in

FIG. 1 by a partially diagrammatic fragmentary section of a typical dualtire automotive vehicle wheel showing the wheel-borne elements of myapparatus associated therewith and by line diagram an electrical circuitwhich may be employed therewith,

FIGS. 2 & 3 constitute composite enlarged fragmentary section of thesaid elements in their normal relation to each other but removed fromthe wheel and FIG. 4 is a fragmentary section on a reduced scale of amodified embodiment of the invention in which spring-loadedswitch-actuating piston is held retracted by a detent responsive to lossof pressure in the tire with which it is associated.

DESCRIPTION OF THE PREFERRED EMBODIMENT I Referring now moreparticularly to the drawing,

there is illustrated in FIG. 1 a typical dual truck wheel 1 on which aremounted in conventional manner pneumatic tires 2,3, in this instanceconfining inner tubes 4,5, with which are connected, respectively, airinjec- In accordance with the invention there is associated with eachtire a tubular control valve 12, having an in-- ,temally threaded endzone 13 complementing the threaded air injection tube 10 and carrying inits bore 14 a detent 15 whereby when the fitting 13 is screwed on tube10 valve stem 1 l is depressed to allow the pressures in the tire and inthe adjacent portion of pressure differential means 12 to attainequilibrium. The op posite end of valve means 12 is releasably connectedthrough an internally threaded fitting 16, with a flexible hose 17 theopposite end of which is connected by a fitting 18 with a metal tube 19,the fittings 16 & 18 being secured to the hose 17 by clamps 20,21,respectively. The metal tube 19 projects through an appropriate hole ina suitable part of the wheel and is secured to a bushing 22 threaded into the wheel body W by a compression collar 23 and gland nut 24 threadedon the other end of bushing 22. The tube 19 projects inwardly toward thevehicle body and carries at its inner end a mechanical component 25,hereinafter more fully described, positioned to follow with the wheel apath adjacent a relatively fixed part P of the vehicle. There is mountedon part P a switch 26 actuated by an arm 27 and controlling the circuitof signal lamp 28 or other alarm device in series with a battery B,which may be the main ignition battery of the vehicle, or any otherenergy source suitable for the purpose.

The components thus far specifically described may be consideredexemplary only and subject to wide modification to suit particularconditions and they may therefore partake of any appropriate form, eachspecifically and individually being found in other associations andforms in apparatus disclosed in the prior art.

In accordance with the invention, however, the component 25 is connectedat the free end of metal tube 19 for rotation with wheel W in a pathadjacent arm 27 of switch 26 and comprises a cylinder 30 containing apiston 31 which carries an elongated piston rod 32 projectibleinto theplane of a path including the switch 26 for actuating the latter whenthe occasion arises.

Air under pressure has access to the cylinder 30 for actuating piston 31from valve stem and with reference to the flow of air from the latter tothe former there is interposed in the connecting conduit providedprincipally by hose l7 and tube 19 pressure-differential valve means 12comprising a cylindrical valve housing 35 at one end threaded onto valvestem 10 and at the other end threaded into fitting 16 carried by hose17. Approximately midway longitudinally bore 36 in housing 35 isconstricted at 37 to form a waist providing at its end nearer tube 10 anannular valve seat receiving a gasket 38 normally engaged by the head 40of a valve poppet 41, spring 42 tends to oppose the tendency of thevalve poppet head to bear in fluid tight relation against gasket 38under the influence of the air pressure being retained thereby in tube10 and the associated tire. This spring 42 is confined in the oppositeend of the bore of valve housing 35 by a threaded bushing 43 receivingthe projecting stem 44 of a control plunger 45 having a bore into whichthe reduced end 46 of the valve poppet stem 47 projects.

It will be apparent the bushing 43 maybe adjusted in the threaded boreof housing 35 so as just to overcome the'air pressure in tube 10 whensuch pressure is unable to maintain valve poppet 41 seated in sealingrelation against valve seat gasket 38 or, if preferred, a spring ofappropriate bias may be selected so the bushing can be fully seated inthe bore.

Obviously when unseating of the valve poppet in this manner occurs dueto decline of air pressure in the associated tire, the air released fromthe latter passes from tube 10 through hose l7 and tube 19 to cylinder30, where it impels piston 31 to project the piston rod 32 axiallyoutwardly with respect to cylinder 30 and thus into an abnormal pathintersected by arm 27 on switch 26. Usually during this operationdisposable dust cap 50 of plastic or other appropriate material,normally protecting cylinder 30 against intrusion of foreign materialsinto its interior, is discharged from the end of the cylinder, to bereplaced, or a like cap substituted for it, after the tire has beenserviced to remedy the lost pressure and the signal apparatus reset.

Outward projection of the piston 31 in the manner just described causesthe piston rod 32, travelling in said abnormal path, to actuate arm 27on engaging it during rotation of the wheel and immediately convey tothe vehicle operator that a tire is deflated or at least under-inflated,while a gasket 51 on the piston rod 32 adjacent the piston head 31 seatsagainst the outer head 52 of cylinder 30 to seal the latter and thusprevent further loss of pressure from the associated tire.

In a modified embodiment of the invention fragmentarily illustrated inFIG. 4 there is utilized instead of the cylinder 30 and air activatedpiston 31 for projecting I piston rod 32 into the path intersected bythe trigger of switch 26 a somewhat different mechanical arrangement ofcomponents, designed to attain comparable results. Thus at the end oftube 19', corresponding to tube 19, there is disposed a spring pressedvalve poppet 41', seating on an annular seat 38' in a bushing 37'threaded into tubular element 12' which is in turn secured to tube 19 bya threaded connection.

The valve poppet 41 is biased by a spring 42' bearing against acollar45' on the valve stem 44' to oppose the seating of the valve by thepressure of air on the poppet head, the stem projecting into atransversely disposed cylinder 30 where it engages in a groove 61 inspring biased piston 31' carrying piston rod 32'.

The engagement of the stem of valve poppet 41' in groove 61 of piston 31restrains spring 62 biasing the piston from projecting the latteroutwardly for driving the piston rod 32 into position for engaging thetrigger of the alarm switch (not shown) corresponding to switch 26,plastic cap 50' being discharged and discarded as the piston rod ejectsit from the end of cylinder 30'.

A lateral fitting 65 containing a standard tire valve,

(not shown) and removable cap 66 communicates with the interior oftubular element 12' and permits the associated tire to be servicedwithout disconnecting the warning apparatus and its employment maysometimes be more convenient than unscrewing the flexible tube connector16 from pressure differential valve means 12.

It will be evident from what has been said that when a tire with whichthe apparatus of my invention, of whatever specific form, may beassociated is subjected to a loss of pneumatic pressure sufficient toenable the pressure-differential responsive control mechanism to becomeactivated the alarm system is energized to advise the operator of thecondition of the corresponding tire. Hence, if desired an independentalarm system for each wheel may be provided, informing the operatorspecifically as to the location of the wheel on which inflation has beenlost, or the switches 26 corresponding to the severalrespective wheelsmay be connected in a single circuit, in which case the operator isadvised by the signal only that at least one tire requires attention,

leaving it to him to determine on inspection which individual tire hasbecome so under-inflated as to activate the alarm.

This inspection is of course an easy one to make since the projection ofa piston rod 32 or 32 from the cylinder containing it may readily beobserved and the appearance of a projected one is adequate evidence ofthe associated tire requiring reinflation as the minimum servicingessential to resumption of normal operation.

It is of course immaterial whether the alarm circuit, including theswitch 26, be of such nature as to be a normally energized one and theswitch one having normally closed contacts, which upon being activatedgive alarm through interruption of a signal as by extinguishment of anormally energized bulb 28, or the switch have normally open contacts soas to energize the circuit and hence light bulb 28 to indicate anabnormal low pressure condition of a tire.

. While some emphasis has herein been laid upon utilization of theapparatus of my invention on relatively heavily burdened vehicles suchas trucks and buses it will be evident it may be employed as well onpassenger automobiles and any other vehicles having pneumatic tires orin fact in any situation in which it is desireable to provideinformation as to the inflation of a moving .object containing a gasunder pressure and adhering to a uniform path or rotation, reciprocationor otherwise.

I claim 1. Apparatus of the character described comprising apressure-differential-responsive valve, a mechanical element carried bya moving structure movable relatively to said structure into a pathabnormal with respect to said structure, a relatively stationarysignalactivating element interposed in said path for actuation by saidelement when in'said abnormal path, means defining a fluid conduitcarried by said structure and pressure responsive means for projectingsaid mechanical element into said abnormal path in response topressure-differential actuation of said valve and introduction therebyof fluid pressure into said conduit from said valve.

2. Apparatus as defined in claim 1 in which the moving structure isrotatable and the relatively stationary signal activating elementcomprises a lever engageable by said mechanical element during itsrotation.

3. Apparatus as defined in claim 1 in which the movsure is released fromthe tire by the pressure-differential-responsive valve.

4. Apparatus of the character described comprising apressure-differential-responsive valve, a mechanical element carried bya moving structure movable into a path abnormal with respect to saidstructure, a relatively stationary signal-activating element interposedin said path for actuation by said element when in said abnormal pathand means carried by said structure for projecting said mechanicalelement into said abnormal path in response to pressure-differentialactuation of said valve, said pressure-differential-responsive valvecomprising a spring biased valve poppet, a substantially cylindricalhousing for the poppet providing a valve seat for the poppet, the springbiasing the poppet away from said seat, and said movable mechanicalelement being adapted to be actuated by fluid under pressure after thespring has separated the poppet from its seat.

5. Apparatus as defined in claim 4 in which the poppet is normally heldin sealing engagement with its seat against the spring bias by fluidpressure in said housing.

6. Apparatus as defined in claim 1 in which said signal activatingelement comprises a housing, a com- -Elementary plunger slidable thereinand a rod carried y the plunger constituting the movable mechanicalelement and being engageable with said signal activating element.

sass:

1. Apparatus of the character described comprising apressuredifferential-responsive valve, a mechanical element carried by amoving structure movable relatively to said structure into a pathabnormal with respect to said structure, a relatively stationarysignal-activating element interposed in said path for actuation by saidelement when in said abnormal path, means defining a fluid conduitcarried by said structure and pressure responsive means for projectingsaid mechanical element into said abnormal path in response topressure-differential actuation of said valve and introduction therebyof fluid pressure into said conduit from said valve.
 1. Apparatus of thecharacter described comprising a pressure-differential-responsive valve,a mechanical element carried by a moving structure movable relatively tosaid structure into a path abnormal with respect to said structure, arelatively stationary signal-activating element interposed in said pathfor actuation by said element when in said abnormal path, means defininga fluid conduit carried by said structure and pressure responsive meansfor projecting said mechanical element into said abnormal path inresponse to pressure-differential actuation of said valve andintroduction thereby of fluid pressure into said conduit from saidvalve.
 2. Apparatus as defined in claim 1 in which the moving structureis rotatable and the relatively stationary signal activating elementcomprises a lever engageable by said mechanical element during itsrotation.
 3. Apparatus as defined in claim 1 in which the movingStructure is a vehicle wheel, the relatively stationary signalactivating element is carried by the vehicle body and said mechanicalelement is actuated by air-pressure derived from the wheel tire when airunder pressure is released from the tire by thepressure-differential-responsive valve.
 4. Apparatus of the characterdescribed comprising a pressure-differential-responsive valve, amechanical element carried by a moving structure movable into a pathabnormal with respect to said structure, a relatively stationarysignal-activating element interposed in said path for actuation by saidelement when in said abnormal path and means carried by said structurefor projecting said mechanical element into said abnormal path inresponse to pressure-differential actuation of said valve, saidpressure-differential-responsive valve comprising a spring biased valvepoppet, a substantially cylindrical housing for the poppet providing avalve seat for the poppet, the spring biasing the poppet away from saidseat, and said movable mechanical element being adapted to be actuatedby fluid under pressure after the spring has separated the poppet fromits seat.
 5. Apparatus as defined in claim 4 in which the poppet isnormally held in sealing engagement with its seat against the springbias by fluid pressure in said housing.